and if were honest it wouldve been terrible

ABC decided against it.
If it's all the same to you, I'll have that drink now.-Loki (Marvel's Avengers)

the spin off spun out of control and crashed.

No other (prior) plan has ever been mentioned it is certainly not impossible. But at the end of season the spin-off was what they had in mind.

No idea. A few people mentioned that Adrienne was on another show now. It can and has been done, but it really is tough to work out television schedules, especially if they're not on the same network.

Does anyone know if there's a chance they'll bring the characters back to the show?

They planned for a while to do the spin-off after S2, but who's to say this was the
original
plan? To me, the whole end of S2 felt very rushed in regard to the relationship between Hunter and Bobbi (and by extension Mack). The whole betrayal arc was never fully resolved. Hunter forgiving Mack came completely out of nowhere and while Bobbi getting shot put an understandable halt to Hunter being mad at her, it didn't resolve their basic issues, either.
To me it always felt as if the fractures between this trio had been mended by force, simply so that the spin-off wouldn't leave any character arcs hanging. Of course, with the spin-off being postponed, that did nothing but basically ruining one of the best arcs of the show and robbing Hunter of tons of character development. So to me, there was nothing that indicated doing Most Wanted post-S2 was the
original
plan.
"We're a team, Garrus. There's no Shepard without Vakarian."

Yup. That was the original idea. But they were kept in the show because they bonded so well with the rest of the cast.

It was widely known and reported on. Just do a time appropriate google search. The "I don't think I can do this anymore" by Bobbi was supposed to be the signifying line iirc.

The original plan was for them to split off after S2.
gotta ask, where did you get this idea?
~Oh, I'm well aware it's not a picnic, Mr. Save the Day~ (Fitz, Agents of Shield)

I'm pretty sure they were gone no matter what. The original plan was for them to split off after S2. That got postponed so that they could re-work the pilot. But they are bringing in new people every year, for a year to
keep it fresh. Of course new people every year means losing some old friends and that's what happened.

Honestly, I wouldn't have cared either way. Do the spin-off or don't. I just wish they would have made up their mind
before
removing my favourite character and OTP from the show!
"We're a team, Garrus. There's no Shepard without Vakarian."

The new president of ABC didn't like it. TBH most of these shows don't get good ratings except at 8 pm et and with no competition in the same genre. With the CW with 4 already established shows in that time period on the CW (M-Th) there was little to be gained other than fratricide.

It died